I'm wondering if this is an animated GIF. And if it is, I don't believe those options are available because SnagIt doesn't know how to deal with editing an animated GIF. There are multiple frames involved.

2. Insert the SnagIt video into PowerPoint (assuming you have PPT). Then add the annotations there and use PPT animation functionality to add things in. Then display the PPT and record it again using SnagIt.